In recent years, medical solution bags constituted by flexible plastic films have become the mainstream of containers for containing medical solutions such as infusion. Medical solution bags of this type have an advantage that they are easy to handle and easy to discard. Because medical solution bags of this type come into direct contact with medical solutions, bags formed of a polyolefin such as polyethylene or polypropylene, the safety of which has been established, are widely used.
Patent literature 1 discloses a medical container constituted by a laminate of an outer layer and an inner layer, the outer layer being formed of a metallocene-catalyzed linear low-density polyethylene or ethylene-α-olefin copolymer having a density of 0.920 to 0.930 g/cm3, the inner layer being formed of a polymer composition that includes a metallocene-catalyzed linear low-density polyethylene or ethylene-α-olefin copolymer having a density of 0.890 to 0.920 g/cm3, a metallocene-catalyzed linear low-density polyethylene or ethylene-α-olefin copolymer having a density of 0.920 to 0.930 g/cm3, and a Ziegler-Natta-catalyzed linear low-density polyethylene or ethylene-α-olefin copolymer having a density of 0.910 to 0.930 g/cm3.
Patent literature 2 discloses a heat resistant sheet formed of a polymer composition that includes 45 to 75% by weight of a metallocene-catalyzed linear polyethylene having a density of 0.928 g/cm3 or more, 5 to 35% by weight of a high-pressure method low-density polyethylene, and 15 to 45% by weight of a metallocene-catalyzed linear polyethylene having a density of 0.91 g/cm3 or less, and an infusion bag formed of this heat resistant sheet.
Patent literature 3 discloses a five-layer plastic film and a container formed of this plastic film, the plastic film including a seal layer comprising a mixture of a propylene-α-olefin random copolymer and a propylene homopolymer, a first flexible layer formed on a surface of the seal layer and comprising a mixture of a propylene·α-olefin random copolymer or the like and an ethylene·α-olefin copolymer elastomer, a reinforcing layer formed on a surface of the first flexible layer and comprising a propylene homopolymer, a polycyclic olefin, or the like, a second flexible layer formed on a surface of the reinforcing layer and comprising the same mixture as that of the first flexible layer, and an outermost layer formed on a surface of the second flexible layer and comprising a propylene homopolymer, a propylene·α-olefin random copolymer, or the like.